<style>
  body {
    background-color: #fff;
  }
</style>
<header id="header" class="header">
  <div class="logo">
    <a href="javascript:;" title="慢慢买">
      <img src="./img/header_logo.png" alt="" />
    </a>
  </div>
  <div class="appdown">
    <a href="javascript:;" title="手机app下载">
      <img src="./img/header_app.png" alt="手机app下载" />
    </a>
  </div>
</header>
<script>
  const num = 11
  console.log(num)
</script>
